High-resolution connector for a neurostimulation lead

ABSTRACT

An implantable connector comprises an electrically insulative housing including an outer wall, an interior cavity surrounded by the outer wall, a port through which the lead body portion can be introduced into the interior cavity, and a pair of first apertures disposed through the outer wall on a first side of the housing. The connector further comprises an electrical spring clip contact mounted to the housing. The contact includes a common portion and a pair of legs extending from opposite ends of the common portion. The legs respectively extend through the first apertures into the interior cavity, such that the legs firmly engage the electrical terminal therebetween when the lead body portion is introduced into the interior cavity.

RELATED APPLICATION

The present application claims the benefit under 35 U.S.C. § 119 to U.S.provisional patent application Ser. No. 61/046,675, filed Apr. 21, 2008.The foregoing application is hereby incorporated by reference into thepresent application in its entirety.

FIELD OF THE INVENTION

The present invention relates to tissue stimulation systems, and moreparticularly, to connectors for coupling neurostimulation leads toimplantable neurostimulators, extension leads, and adapters.

BACKGROUND OF THE INVENTION

Implantable neurostimulation systems have proven therapeutic in a widevariety of diseases and disorders. Pacemakers and Implantable CardiacDefibrillators (ICDs) have proven highly effective in the treatment of anumber of cardiac conditions (e.g., arrhythmias). Spinal CordStimulation (SCS) systems have long been accepted as a therapeuticmodality for the treatment of chronic pain syndromes, and theapplication of tissue stimulation has begun to expand to additionalapplications such as angina pectoralis and incontinence. Deep BrainStimulation (DBS) has also been applied therapeutically for well over adecade for the treatment of refractory chronic pain syndromes, and DBShas also recently been applied in additional areas such as movementdisorders and epilepsy. Further, in recent investigations PeripheralNerve Stimulation (PNS) systems have demonstrated efficacy in thetreatment of chronic pain syndromes and incontinence, and a number ofadditional applications are currently under investigation. Also,Functional Electrical Stimulation (FES) systems such as the Freehandsystem by NeuroControl (Cleveland, Ohio) have been applied to restoresome functionality to paralyzed extremities in spinal cord injurypatients.

Each of these implantable neurostimulation systems typically includesone or more stimulation leads implanted at the desired stimulation site.In the context of an SCS procedure, one or more stimulation leads areintroduced through the patient's back into the epidural space underfluoroscopy, such that the electrodes carried by the leads are arrangedin a desired pattern and spacing to create an electrode array.

The specific procedure used to implant the stimulation leads in an SCSprocedure will ultimately depend on the type of stimulation leads used.Currently, there are two types of commercially available stimulationleads: a percutaneous lead and a surgical lead.

A percutaneous lead comprises a cylindrical body with ring electrodes,and can be introduced into contact with the affected spinal tissuethrough a Touhy-like needle, which passes through the skin, between thedesired vertebrae, and into the epidural space above the dura layer. Forunilateral pain, a percutaneous lead is placed on the correspondinglateral side of the spinal cord. For bilateral pain, a percutaneous leadis placed down the midline of the spinal cord, or two percutaneous leadsare placed down the respective sides of the midline. In many cases, astylet, such as a metallic wire, is inserted into a lumen runningthrough the center of each of the percutaneous leads to aid in insertionof the lead through the needle and into the epidural space. The styletgives the lead rigidity during positioning, and once the lead ispositioned, the stylet can be removed after which the lead becomesflaccid.

A surgical lead has a paddle on which multiple electrodes are arrangedin independent columns, and is introduced into contact with the affectedspinal tissue using a surgical procedure, and specifically, alaminectomy, which involves removal of the laminar vertebral tissue toallow both access to the dura layer and positioning of the lead.

Each of the above-mentioned implantable neurostimulation systems alsocomprises an implantable neurostimulator, such as an implantable pulsegenerator (IPG), implanted remotely from the stimulation site, butcoupled to the stimulation leads. Thus, electrical pulses can bedelivered from the neurostimulator to the stimulation leads to stimulatethe tissue and provide the desired efficacious therapy to the patient.In the context of an SCS procedure, the electrical pulses are deliveredto the dorsal column and dorsal root fibers within the spinal cord. Thestimulation creates the sensation known as paresthesia, which can becharacterized as an alternative sensation that replaces the pain signalssensed by the patient.

Each stimulation lead may be directly coupled to the neurostimulator orindirectly coupled to the neurostimulator via an extension leads incases where the length of the stimulation leads is insufficient to reachthe neurostimulator.

If the stimulation leads are to be directly connected to theneurostimulator, the proximal ends of the stimulation leads can beinserted into a connector of the neurostimulator (via connector portslocated on a header of the neurostimulator), such that the terminalslocated at the proximal ends of the stimulation leads are coupled tocorresponding electrical contacts within the connector. Individual wiresare routed though lumens in each stimulation lead to connect theproximally-located terminals with the distally-located electrodes.

If the stimulation leads are to be indirectly connected to theneurostimulator via the extension leads, the proximal ends of thestimulation leads can be inserted into connectors located at the distalends of the respective extension leads, such that the terminals of thestimulation leads are coupled to corresponding electrical contactswithin the connectors of the extension leads. The proximal ends of theextension leads can then be inserted into the connector of theneurostimulator, such that terminals located at the proximal ends of theextension leads are coupled to the corresponding electrical contactswithin the connector of the neurostimulator. Individual wires are routedthough lumens in each extension lead to respectively couple theproximally-located terminals to the distally-located electricalcontacts.

After the system is fully implanted, it is important that thesubcutaneously implanted components, such as the neurostimulator andextension leads, be of a low-profile nature for aesthetic reasons aswell as to prevent or minimize any discomfort of the patient that mayotherwise occur by having rigid objects that do not conform to thenatural curvature and movement of the patient.

However, in order to accommodate the present-day contacts, which eithertake the form of metal collars containing set screws or Bal-Seal®contacts composed of springs contained within steel ring housings, theconnectors of the extension lead and adapter are typically larger andstiffer than the bodies of the extension lead and adapter, therebyincreasing the overall profile, while decreasing the conformity, of theextension lead and adapter. In addition, Bal-Seal® contacts are alsorelatively expensive, which given the number of contacts required, mayresult in a connector that is prohibitively expensive. Furthermore,metal collars for accommodating screws and the spring coil within theBal-Seal® contacts are relatively long, thereby limiting the number ofcontacts that can be incorporated into a connector. Although the currentconnector designs can accommodate up to eight Bal-Seal® contacts, futureconnector designs will need to accommodate more contacts (e.g., 12-16).However, in order to accomplish this using Bal-Seal® contacts, thelength of the connector would have to be increased, which may beunacceptable.

There, thus, remains a need for a lower-profile, high resolutionconnector for an electrical lead assembly.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, animplantable connector for receiving an electrical lead body portion thatcarries an electrical terminal is provided. The implantable connectorcomprises an electrically insulative housing including an outer wall(e.g., a cylindrical wall) an interior cavity surrounded by the outerwall, a port through which the lead body portion can be introduced intothe interior cavity, and a pair of first apertures disposed through theouter wall on a first side of the housing. The implantable connectorfurther comprises an electrical spring clip contact mounted to thehousing. The contact includes a common portion and a pair of legsextending from opposite ends of the common portion. The legsrespectively extend through the first apertures into the interiorcavity, such that the legs firmly engage the electrical terminaltherebetween when the lead body portion is introduced into the interiorcavity.

In one embodiment, the housing is less compliant than the contact, suchthat the housing does not deform when the legs firmly engage theterminal. In another embodiment, the portions of the legs within theinterior cavity are radiused outward, such that the radiused portions atleast partially wrap around the electrical terminal when the lead bodyportion is introduced into the interior cavity. In still anotherembodiment, the housing further comprises at least one opening disposedthrough the outer wall on a second side of the housing opposite thefirst side of the housing, wherein the legs extend from the interiorcavity through the at least one opening. As one example, the opening(s)can comprise a pair of second apertures, in which case, the legsrespectively extend from the interior cavity through the secondapertures. As another example, the opening(s) can comprise an axial slotextending along a length of the outer wall, in which case, the legsextend from the interior cavity through the axial slot.

In yet another embodiment, the housing further includes a recess withinan external surface of the housing between the first apertures, suchthat the common portion is seated within the recess. In this case, therecess may have a depth, such that the common portion does not extendabove the external surface of the housing. The housing may furtherinclude at least one recess within an external surface of the housingadjacent the at least one opening, wherein ends of the legs are curved,such that they are seated within the at least one recess. In anotherembodiment, the implantable connector further comprises a tubular sealdisposed within the housing around the interior cavity. The sealincludes a pair of apertures that coincide within the first apertures,wherein the legs respectively extend through the apertures of the sealinto the interior cavity of the receptacle. The implantable connectormay further comprise an electrical conductor connected to the contact,and an electrically insulative cover disposed over the housing andcommon portion.

In another embodiment, the lead body portion carries a plurality ofelectrical terminals. In this case, the housing further includes aplurality of pairs of first apertures disposed through the outer wall,and axially spaced apart along a length of the housing. The implantableconnector further comprises a plurality of electrical spring clipcontacts mounted to the housing, with each of the contacts including acommon portion and a pair of legs extending from opposite ends of thecommon portion. The legs of each contact respectively extend through adifferent pair of the first apertures into the interior cavity, suchthat the legs firmly engage a respective electrical terminaltherebetween when the lead body portion is introduced into the interiorcavity.

In accordance with a second aspect of the present inventions, animplantable lead assembly is provided. The implantable lead assemblycomprises the lead body portion described above, and another electricallead having another lead body portion and the connector carried by theother lead body portion.

In accordance with a third aspect of the present inventions, a method ofmanufacturing the connector comprising inserting the legs through thefirst apertures into the interior cavity. The method may furthercomprise inserting the legs from the interior cavity through at leastone opening disposed through the outer wall on a second side of thehousing opposite to the first side of the housing. The method mayfurther comprise crimping each arm to form a radiused portion, such thatthe radiused portions are disposed within the interior cavity when thelegs are respectively inserted through the first apertures. The methodmay further comprise introducing a tubular seal into the interiorcavity, such that the legs are respectively introduced through a pair ofapertures within the seal after the legs are introduced through the pairof first apertures in the outer wall. The method may further compriseapplying an electrically insulative cover to an exterior surface of thehousing.

Other and further aspects and features of the invention will be evidentfrom reading the following detailed description of the preferredembodiments, which are intended to illustrate, not limit, the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the design and utility of preferred embodimentsof the present invention, in which similar elements are referred to bycommon reference numerals. In order to better appreciate how theabove-recited and other advantages and objects of the present inventionsare obtained, a more particular description of the present inventionsbriefly described above will be rendered by reference to specificembodiments thereof, which are illustrated in the accompanying drawings.Understanding that these drawings depict only typical embodiments of theinvention and are not therefore to be considered limiting of its scope,the invention will be described and explained with additionalspecificity and detail through the use of the accompanying drawings inwhich:

FIG. 1 is plan view of one embodiment of a prior art tissue stimulationsystem;

FIG. 2 is a plan view of the tissue stimulation system of FIG. 1 in usewith a patient;

FIG. 3 is a profile view of a proximal end of a prior art stimulationlead used in the tissue stimulation system of FIG. 1;

FIG. 4 is a profile view of a distal end of a prior art stimulation leadused in the tissue stimulation system of FIG. 1;

FIG. 5 is a cross-sectional view of the stimulation lead of FIG. 4,taken along the line 5-5;

FIG. 6 is an exploded view of one embodiment of a connector constructedin accordance with the present inventions, which can be used in thetissue stimulation system of FIG. 1;

FIG. 7 is one perspective view of the connector of FIG. 6;

FIG. 8 is another perspective view of the connector of FIG. 6;

FIG. 9 is still another perspective view of the connector of FIG. 6;

FIG. 10 is a perspective view of the connector of FIG. 6, particularlyshowing an outer housing of the connector in phantom;

FIG. 11 is a cross-sectional view of the connector of FIG. 6;

FIG. 12 is a side view of the connector of FIG. 6;

FIG. 13 is a top view of an outer housing used in the connector of FIG.6;

FIG. 14 is a bottom view of the outer housing of FIG. 13;

FIG. 15 is a cross-sectional view of the outer housing of FIG. 13;

FIG. 16 is a cross-sectional perspective view of the outer housing ofFIG. 13;

FIG. 17 is a perspective view of an electrical spring clip contact usedin the connector of FIG. 6;

FIG. 18 is a perspective view of a tubular seal used in the connector ofFIG. 6;

FIG. 19 is a cross-sectional view of the tubular seal of FIG. 18;

FIG. 20 is a perspective view of a connector block used in the connectorof FIG. 6;

FIG. 21 is a cross-sectional view a subassembly of the connector of FIG.6, particularly showing the outer housing, tubular seal, and connectorblock;

FIG. 22 is a perspective view of the electrical spring clip contact ofFIG. 17, particularly showing the distal ends of the legs uncrimped;

FIG. 23 is a perspective view of a subassembly of the connector of FIG.6, particularly showing the outer housing, tubular seal, connectorblock, and uncrimped pins;

FIG. 24 is an exploded view of another embodiment of a connectorconstructed in accordance with the present inventions, which can be usedin the tissue stimulation system of FIG. 1;

FIG. 25 is one perspective view of the connector of FIG. 24;

FIG. 26 is another perspective view of the connector of FIG. 24;

FIG. 27 is still another perspective view of the connector of FIG. 24;

FIG. 28 is a cross-sectional view of the connector of FIG. 24;

FIG. 29 is a perspective view of an outer housing used in the connectorof FIG. 24;

FIG. 30 is a cross-sectional view of the outer housing of FIG. 29;

FIG. 31 is a perspective view of a tubular seal used in the connector ofFIG. 24;

FIG. 32 is a cross-sectional view of the tubular seal of FIG. 31;

FIG. 33 is a cross-sectional view a subassembly of the connector of FIG.24, particularly showing the outer housing and tubular seal;

FIG. 34 is a cross-sectional view a subassembly of the connector of FIG.24, particularly showing the outer housing, tubular seal, connectorblock, and end cap;

FIG. 35 is a perspective view of a subassembly of the connector of FIG.24, particularly showing the outer housing, tubular seal, connectorblock, and uncrimped pins;

FIG. 36 is an exploded view of still another embodiment of a connectorconstructed in accordance with the present inventions, which can be usedin the tissue stimulation system of FIG. 1;

FIG. 37 is one perspective view of the connector of FIG. 36;

FIG. 38 is another perspective view of the connector of FIG. 36;

FIG. 39 is still another perspective view of the connector of FIG. 36;

FIG. 40 is a perspective view of the connector of FIG. 36, particularlyshowing an outer housing of the connector in phantom;

FIG. 41 is a cross-sectional view of the connector of FIG. 36;

FIG. 42 is a side view of the connector of FIG. 36;

FIG. 43 is a top view of an outer housing used in the connector of FIG.36;

FIG. 44 is a cross-sectional view of the outer housing of FIG. 43, takenalong the axis of the housing;

FIG. 45 is a cross-sectional view of the outer housing of FIG. 43, takentransversely to the axis of the housing;

FIG. 46 is a perspective view of an electrical spring clip contact usedin the connector of FIG. 36;

FIG. 47 is a perspective view of a seal used in the connector of FIG.36; and

FIG. 48 is a cross-sectional view a subassembly of the connector of FIG.36, particularly showing the legs of the contact spread outward.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The description that follows relates to a spinal cord stimulation (SCS)system. However, it is to be understood that while the invention lendsitself well to applications in SCS, the invention, in its broadestaspects, may not be so limited. Rather, the invention may be used withany type of implantable electrical circuitry used to stimulate tissue.For example, the present invention may be used as part of a pacemaker, adefibrillator, a cochlear stimulator, a retinal stimulator, a stimulatorconfigured to produce coordinated limb movement, a cortical stimulator,a deep brain stimulator, peripheral nerve stimulator, microstimulator,or in any other neural stimulator configured to treat urinaryincontinence, sleep apnea, shoulder sublaxation, headache, etc.

Referring first to FIGS. 1 and 2, a generalized tissue stimulationsystem 10 that may be used in spinal cord stimulation (SCS), as well asother stimulation applications, will be described. The stimulationsystem 10 generally comprises an implantable neurostimulator 12, animplantable stimulation lead 14, which carries an array of electrodes18, and an implantable extension lead 16. Although only one stimulationlead 14 is shown, more than one stimulation lead, and typically twostimulation leads, can be used in the stimulation system 10. As thereshown, the proximal end of the stimulation lead 14 is removably mated tothe distal end of the extension lead 16 via a connector 20 associatedwith the extension lead 16, and the proximal end of the extension lead16 is removably mated to the neurostimulator 12 via a connector 22associated with the neurostimulator 12.

In the illustrated embodiment, the neurostimulator 12 takes the form ofan implantable pulse generator (IPG) that comprises an electronicsubassembly 24 (shown in phantom), which includes control and pulsegeneration circuitry (not shown) for delivering electrical stimulationenergy to the electrodes (described below) of the stimulation lead 14 ina controlled manner, and a power supply, e.g., a battery 26 (shown inphantom), so that once programmed and turned on by an externalprogramming device (not shown), the neurostimulator 12 can operateindependently of external hardware.

Alternatively, the neurostimulator 12 can take the form of animplantable receiver-stimulator (not shown), in which case, the powersource, e.g., a battery, for powering the implanted receiver, as well ascontrol circuitry to command the receiver-stimulator, will be containedin an external controller inductively coupled to the receiver-stimulatorvia an electromagnetic link. Alternatively, the neurostimulator 12 cantake the form of an external trial stimulator (ETS)(not shown), whichhas similar pulse generation circuitry as an IPG, but differs in that itis a non-implantable device that is used on a trial basis after thestimulation lead 14 has been implanted and prior to implantation of theIPG, to test the responsiveness of the stimulation that is to beprovided.

The neurostimulator 12 comprises an outer housing 28 for housing theelectronic and other components (described in further detail below), andthe connector 22 to which the proximal end of the stimulation lead 14(or optionally the proximal ends of the extension leads 16) mates in amanner that electrically couples the electrodes 18 to the pulsegeneration circuitry contained within the outer housing 28. The outerhousing 28 may be composed of a biocompatible material, such astitanium, and forms a hermetically sealed compartment wherein theelectronic subassembly 24 and battery 26 are protected from the bodytissue and fluids. The connector 22 is disposed in a portion of thehousing 28 that is, at least initially, not sealed.

As will be described in further detail below, the connector 22 carries aplurality of contacts that come into electrical contact with therespective terminals (described in further detail below) of thestimulation lead 14 or extension lead 16 when the proximal end of thestimulation lead 14 or extension lead 16 is inserted into the connector22. Electrical conductors (not shown), which extend from the connector22 in electrical contact with the contacts, penetrate the housing 28into the sealed chamber and connect to the electronic subassembly 24.Additional details discussing neurostimulators, including the outerhousing 28 and connector 22, are disclosed in U.S. patent applicationSer. No. 11/327,880, entitled “Connector and Methods of Fabrication,”which is expressly incorporated herein by reference.

As shown in FIG. 2, the stimulation lead 14 is implanted in the epiduralspace 30 of a patient in close proximity to the spinal cord 32. Becauseof the lack of space near the lead exit point 34 where the stimulationlead 14 exits the spinal column, the neurostimulator 12 is generallyimplanted in a surgically-made pocket either in the abdomen or above thebuttocks. The neurostimulator 12 may, of course, also be implanted inother locations of the patient's body. Use of the extension lead 16facilitates locating the neurostimulator 12 away from the lead exitpoint 34. In addition, in some cases, the extension lead 16 may serve asa lead adapter if the proximal end of the stimulation lead 14 is notcompatible with the connector of the neurostimulator 12 (e.g., differentmanufacturers use different connectors at the ends of their stimulationleads and are therefore not compatible with the connector heads of theneurostimulator of another manufacturer). The extension lead 16 may bemade to adapt the stimulation lead 14 to connect the neurostimulator 12to the stimulation lead 14, and hence, “adapt” the stimulation lead 14to the neurostimulator 12.

Referring further to FIGS. 3 and 4, the stimulation lead 14 comprises anelongated lead body 40 having a proximal end 42 and a distal end 44. Thelead body 40 may, e.g., have a diameter of between about 0.03 inches to0.07 inches and a length within the range of 30 cm to 90 cm for spinalcord stimulation applications. The lead body 40 may be composed of asuitable electrically insulative material, such as, a polymer (e.g.,polyurethane or silicone), and may be extruded from as a unibodyconstruction.

The stimulation lead 14 further comprises a plurality of terminals 46mounted to the proximal end 42 of the lead body 40 (FIG. 3), and theplurality of electrodes 18 mounted to the distal end 44 of the lead body40 (FIG. 4). In the illustrated embodiment, the stimulation lead 14 is apercutaneous lead, and to this end, the electrodes 18 are arrangedin-line along the lead body 40. In an alternative embodiment, thestimulation lead may take the form of a single paddle lead (not shown),in which case the electrodes 18 may be arranged in a two-dimensionalpattern on one side of a paddle. Further details regarding theconstruction and method of manufacture of paddle leads are disclosed inU.S. patent application Ser. No. 11/319,291, entitled “Stimulator Leadsand Methods for Lead Fabrication,” the disclosure of which is expresslyincorporated herein by reference.

Although the stimulation lead 14 is shown as having sixteen terminals 46(FIG. 3) and sixteen corresponding electrodes 18 (FIG. 4), the number ofterminals and electrodes may be any number suitable for the applicationin which the stimulation lead 14 is intended to be use (e.g., two, four,sixteen, etc.). Each of the terminals 46 and electrodes 18 takes theform of a cylindrical ring element composed of an electricallyconductive, biocompatible, non-corrosive, material, such as, e.g.,platinum, titanium, stainless steel, or alloys thereof.

The stimulation lead 14 further includes a plurality of electricallyinsulative spacers 48 located on the lead body 40 between the respectiveterminals 46 and electrodes 18. The spacers 48 may be composed of asuitable material, such as, a polymer (e.g., polyurethane or silicone).The stimulation lead 14 further includes an optional retention sleeve 50located at the proximal end 42 of the lead body 40 just distal to theterminals 46. The retention sleeve 50 serves as a hard surface for amechanical securing element, such as a set screw (not shown), used tosecure the proximal end of the stimulation lead 14 within a connector(e.g., either carried by the extension lead or the neurostimulator). Thestimulation lead 14 further comprises an optional radiopaque marker 52located at the distal tip of the lead body 40.

As shown in FIG. 5, the stimulation lead 14 also includes a plurality ofelectrical conductors 54 (each comprising individual strands 56)extending through individual lumens 57 within the lead body 40 andconnected between the respective terminals 46 and electrodes 18 usingsuitable means, such as welding, thereby electrically coupling theproximally-located terminals 46 with the distally-located electrodes 18.In the illustrated embodiment, the conductor 54 is a multfilar cable(1×19 or 1×7) wire made from 28% inner core of pure silver with 78%outer cladding of MP35N stainless steel. The conductor 54 is theninsulated with a thin outer jacket (0.001″ thick) of EthyleneTetrafluoroethylene (ETFE) fluoro-based polymer. In the illustratedembodiment, the conductors 54 can be pre-cut and two zones on the ETFEinsulation pre-ablated where they are connected between the respectiveelectrode 18 and terminal 46. The stimulation lead 14 further includes acentral lumen 58 that may be used to accept an insertion stylet (notshown) to facilitate lead implantation.

Further details describing the construction and method of manufacturingstimulation leads are disclosed in U.S. patent application Ser. No.11/689,918, entitled “Lead Assembly and Method of Making Same,” and U.S.patent application Ser. No. 11/565,547, entitled “CylindricalMulti-Contact Electrode Lead for Neural Stimulation and Method of MakingSame,” the disclosures of which are expressly incorporated herein byreference.

Referring back to FIG. 1, the extension lead 16 is similar to thestimulation lead 14 in that it comprises an elongated lead body 60having a proximal end 62 and a distal end 64, and a plurality ofterminals (not shown) mounted to the proximal end 62 of the lead body60. The lead body 60 of the extension lead 16 may be similarlydimensioned and constructed as the lead body 40 of the stimulation lead14. The extension lead 16 may also include retention sleeve (not shown)much like the retention sleeve 50 of the stimulation lead 14.

The extension lead 16 differs from the stimulation lead 14 in that,instead of electrodes, it comprises the previously mentioned connector20 mounted to the distal end 64 of the lead body 60. The connector 20 isconfigured to accept the proximal end 42 of the stimulation lead 14. Aswill be described in further detail below, the connector 20 carries aplurality of contacts that come into electrical contact with therespective terminals 46 of the stimulation lead 14 when the proximal end42 of the stimulation lead 14 is inserted into the connector 20. In asimilar manner as the stimulation lead 14 (shown in FIG. 5), theextension lead 16 also includes a plurality of electrical conductorsextending through individual lumens (both not shown) within the leadbody 60 and connected between the respective terminals and contactsusing suitable means, such as welding, thereby electrically coupling theproximally-located terminals with the distally-located contacts.

Referring now to FIGS. 6-12, one embodiment of a connector 100 that canbe incorporated into the extension lead 16 and/or neurostimulator 12(shown in FIGS. 1 and 2) will be described. As will be described infurther detail below, the connector 100 can receive the proximal end ofan electrical lead, which can be firmly engaged and locked within theconnector 100. The electrical lead may be, e.g., the stimulation lead 14or the extension lead 16 (shown in FIGS. 1 and 2), depending on whetheran extension lead is used in the lead assembly and whether the connector100 is incorporated into an extension lead or in a neurostimulator. Thatis, if the connector 100 is to be located in an extension lead, theelectrical lead that is mated within the connector 100 will be thestimulation lead. If the connector 100 is to be located in aneurostimulator, the electrical lead that is mated within the connector100 will be the extension lead if used in the lead assembly and will bethe stimulation lead if the extension lead is not used in the leadassembly.

The connector 100 generally comprises (1) an electrically insulativehousing 102 for receiving the proximal end of the electrical lead; (2) aplurality of electrical spring clip contacts 104 (in this case, sixteencontacts) incorporated into the housing 102, such that contacts 104firmly engage the terminals of an electrical lead that is received intothe housing 102; (3) an electrically insulative seal 106 to ensure thatthe contacts 104, and thus the terminals in engagement with the contacts104, are electrically isolated from each other; (4) a connector block108 associated with the housing 102 to lock the electrical lead withinthe housing 102; (5) a plurality of electrical conductors (not shown)connected to the respective contacts 104; and (6) an optionalelectrically insulative covering (not shown) disposed over the housing102.

Referring further to FIGS. 13-16, the housing 102 (shown in phantom inFIG. 10) includes an outer wall 110, an interior passage 112 (shown bestin FIGS. 15 and 16) circumferentially surrounded by the outer wall 110,a port 114 (shown best in FIGS. 13-15) into which the proximal end ofthe electrical lead can be introduced, and an end cap 116 opposite theport 114, which serves as an insertion stop for the electrical lead. Inthe illustrated embodiment, the outer wall 110 takes the form of acylinder having an open end that forms the port 114 and a closed endthat forms the end cap 116. The dimensions and composition of the outerwall 110 are preferably selected, such that the housing 102 is lesscompliant than the contacts 104 that are to be mounted in the housing102, such that the housing 102 does not substantially deform when thecontacts 104 engage the terminals of the electrical lead, therebymaintain the spacing and orientation of the contacts 104 relative toeach other, as will be described in further detail below. For example,the length of the outer wall 110 may be in the range of 1-2 inches, theouter diameter of the outer wall 110 may be in the range of 0.18-0.20inches, the thickness of the outer wall 110 may be in the range of0.025-0.040 inches, and the material from which the outer wall 110 iscomposed may be polycarbonate or polyetheretherketone (PEEK).

To accommodate the contacts 104, the housing 102 includes a pattern ofapertures and recesses formed within the outer wall 110 using suitablemeans, such as laser ablation or molding.

In particular, the housing 102 includes pairs of contact entry apertures118 (best shown in FIGS. 13, 15, and 16) extending through the outerwall 110. The aperture 118 of each pair are circumferentially spacedfrom each other a specific distance, which as will be described infurther detail below will depend on the dimensions of the contacts 104.The apertures 118 of each pair are also axially aligned with each other(i.e., they are disposed along the axis of the outer housing 102 thesame distance). The aperture pairs 118 are axially spaced from eachother a specific distance. In the illustrated embodiment, the axialspacing is uniform between the respective aperture pairs 118, althoughin alternative embodiments, the axial spacing between the respectiveaperture pairs 118 may be non-uniform. The axial spacing will ultimatelydepend on the length of the outer wall 110 and the number of contacts104 that will be incorporated into the connector 100. The aperture pairs118 are also circumferentially aligned with each other (i.e., they areclocked around the axis the same angle). For example, as illustrated inFIG. 13, the aperture pairs 18 are all shown at the top of the outerwall 110 (or the 12 o'clock position). In alternative embodiments, theaperture pairs 118 may be circumferentially misaligned or staggered.

The housing 102 further includes pairs of contact exit apertures 120(best shown in FIGS. 14, 15, and 16) extending through the outer wall110. Like the contact entry apertures 118, the contact exit apertures120 of each pair are circumferentially spaced from each other a specificdistance, and in particular, the same distance as the contact entryapertures 118 are circumferentially spaced from each other. The contactexit apertures 120 of each pair are also axially aligned with eachother. The aperture pairs 120 are axially spaced from each other thesame distance as the contact entry aperture pairs 120, and arecircumferentially opposite the respective entry aperture pairs 118(i.e., each corresponding contact entry aperture pair 118 and contactexit pair 120 are clocked from each other 180 degrees). Thus, becausethe contact entry aperture pairs 118 are circumferentially aligned, thecontact exit aperture pairs 120 are likewise circumferentially aligned.

The housing 102 further includes a channeled recess 122 (best shown inFIGS. 13 and 16) formed in the exterior surface of the outer wall 110adjacent each contact entry aperture pair 118, and a channeled recess124 (best shown in FIGS. 14 and 16) formed in the exterior surface ofthe outer wall 110 adjacent each contact exit aperture pair 124. In theillustrated embodiment, each channeled recess 122 circumferentiallyextends between contact entry apertures 118 of each respective pair, andeach channeled recess 124 circumferentially extends between andoutwardly away from the contact exit apertures 120 of each respectivepair. In alternative embodiments, two channeled recesses (not shown) maycircumferentially extend away from the contact exit apertures 120 ofeach respective pair (i.e., there is no recess between the contact exitapertures 120) or the channeled recess may only extend between thecontact exit apertures 120.

Referring to FIG. 17, each of the contacts 104 is formed from acylindrical wire composed of a suitably electrically conductive andresilient material, such as platinum, titanium, stainless steel, oralloys thereof. For example, the contacts 104 may be composed ofplatinum-iridium alloy (90% Pt-10% Iridium), MP35N nickel-steel, and 316stainless steel. The diameter of the wire from which each contact 104 isformed is preferably of a suitable size to provide the necessary springforce to firmly engage the respective terminal. For example, the wirecan have a diameter in the range of 0.008-0.015 inches. Significantly,the relatively small diameter of the wire used to make the contacts 104,as compared to Bal-Seal® contacts (which have a length of 0.055 inches),allows many more electrical contacts to be incorporated into theconnector 100 at a much cheaper cost.

Each of the contacts 104 includes a common portion 126 and a pair oflegs 128 extending downward from opposite ends of the common portion126. The length of the common portion 126 equals the distance betweenthe contact entry apertures 118 of each pair, such that the axes of thelegs 128 will coincide with the contact entry apertures 118. The lengthof each of the respective legs 128 is greater than the distance betweenthe corresponding apertures 118, 120 through the interior passage 112,such that the legs 128 can completely extend through the interiorpassage 112.

As shown in FIGS. 7-9 and 11, the legs 128 of each contact 104 extendthrough a respective pair of contact entry apertures 118 into theinterior passage 112 of the housing 102, such that the common portion126 of the respective contact 104 is seated within the recess 122extending between the contact entry apertures 118, and the middleportions 130 of the legs 128 firmly engage the respective electricalterminal (not shown) therebetween when the proximal end of theelectrical lead is introduced into the internal passage 112. In theillustrated embodiment, the middle portions 130 of the legs 128 areradiused outward, such that the middle portions 130 at least partiallywrap around the electrical terminal when the lead body portion isintroduced into the interior passage 112. As a result, a greater contactsurface between the contact 104 and the respective terminal is achieved,thereby providing a more secure engagement therebetween.

The legs 128 of each contact 104 further extend from the interiorpassage 112 of the housing 102 and through the contact exit apertures120, such that end portions 132 of the legs 128 are disposed externallyto the outer housing 102. The end portions 132 of the legs 128 arecurved outward back towards the common portion 126, such that they areseated within the recess 124 extending outwardly from the contact exitapertures 120. In the alternative case where there is a recess onlybetween the contact exit apertures 120, the end portions 132 of the legs128 (if made shorter) can be curved inward towards each other, such thatthey are both seated in the recess. The end portions 132 of the legs 128may be curved using suitable means, such as a crimping tool. Preferably,the depth of the recesses 122, 124 is equal to or greater than diameterof the wire from which the contact 104 is formed, so that no portion ofthe common portions 126 or legs 128 extends above the external surfaceof the outer wall 110.

Referring to FIGS. 10 and 11, the tubular seal 106 is disposed withinthe housing 102, and in particular, is interference fit with theinterior surface of the housing 102, such that seal 106 surrounds theinterior passage 112. The tubular seal 106 may be composed of anyelectrically insulative and compliant material, such as silicone.

Referring further to FIGS. 18 and 19, the tubular seal 106 includes acylindrical wall 134 having a diameter substantially the same as theinner diameter of the housing 102, such that the tubular seal 106 issnugly fit within the interior passage 112 of the housing 102. Thetubular seal 106 includes pairs of contact entry apertures 136 (only oneshown) that are coincident with the pairs of contact entry apertures 118(shown in FIG. 13) of the housing 102, and pairs of contact exitapertures 138 (only one shown) that are coincident with the pairs ofcontact exit apertures 120 (shown in FIG. 14) of the housing 102. Thus,the legs 128 of each contact 104 extend from the contact entry apertures118 of the housing 102, through the contact entry apertures 136 of theseal 106, and into the interior passage 112. The legs 128 of eachcontact 104 also extend from the interior passage 112, through thecontact exit apertures 138 of the seal 106, and then through the contactexit apertures 122 of the housing 102.

Notably, as best shown in FIG. 11, the contact entry apertures 136 andcontact exit apertures 138 of the seal 106 are smaller than the diameterof wire from which the respective contact 104 is composed, such that theapertures 136, 138 conform to, and thereby seal, against the outersurface of the contacts 104. As a result, electrical isolation betweenthe contacts 104, and therefore the terminals of the lead (not shown),is increased. To further maximize isolation between the electricalcontacts 104, the seal 106 further includes a plurality of inner annularflanges 140 that extend along the length of the seal 106 into theinterior passage 112 between the respective contacts 104, such that whenthe proximal end of the electrical lead is inserted into the interiorpassage 112 and through center openings 142 in the annular flanges 140,the annular flanges 140 will conform to, and thereby seal, against theouter surface of the electrical lead. As a result, even if anelectrolytic fluid enters the interior passage 112 of the outer housing102, the annular flanges 140 will prevent or, at least minimize, theleakage of electrical current between the contacts 104.

Referring to FIG. 20, the connector block 108 serves a rigid platformfor supporting the forces applied to the set screw. To this end,connector block 108 includes an annular flange 144 that is mountedwithin the port 114 of the housing 102 (best shown in FIG. 10) usingsuitable means, such as bonding, and a bore 146 leading to the annularflange 144 into the port 114 of the outer housing 102. Thus, theproximal end of the electrical lead can be inserted through the bore 146of the connector block 108 and into the port 114 of the housing 102. Theconnector block 108 further includes a threaded bore 148 disposedorthogonally to the bore 146. A tool (e.g., a torque wrench) may beinserted into the threaded bore 148 to tighten or loosen a set screw(not shown) that can be used to firmly secure the electrical lead (e.g.,by frictionally engaging a retention sleeve 50 shown in FIG. 3) withinthe outer housing 102. The connector block 108 can be composed of anysuitable conductor or non-conductive material, such as, e.g.,non-conductive polymers, polyetheretherketone (PEEK), ceramics, etc.,metal, alloys, conductive polymers, conductive carbon, etc.

The electrical conductors (not shown) are respectively connected to thecontacts 104 using suitable techniques known in the art, such aswelding. If the connector 100 is incorporated into an electrical lead,such as an extension lead, the electrical conductors take the form ofwires that are routed through the housing 102 (e.g., the electricalconductors 54 shown in FIG. 5) and then through a lead body (not shown)that extends from the connector 100. If the connector 100 isincorporated into a neurostimulator, the electrical conductors extendout from corresponding openings (not shown) made in the housing 102.

The electrically insulative cover (not shown) may be composed of asuitably electrically insulative material (such as, e.g. silicone orpolyurethane). The cover is disposed over the housing 102 in such amanner that all exposed surfaces of the contacts 104 are covered, andthereby electrically insulated from each other if the connector 100comes in contact with tissue or fluids.

Referring to FIGS. 21-23, a method of assembling the componentsillustrated in FIG. 6 into the connector 100 illustrated in FIGS. 7-12will now be described. First, as illustrated in FIG. 21, the seal 106 isinserted into the interior passage 112 of the housing 102 via the port114, such that the seal 106 and housing 112 are interference fit witheach other, and the annular flange 144 of the connector block 108 isinserted into the port 114, such that the annular flange 144 abuts theseal 106. The annular flange 144 of the connector block 108 may beaffixed within the port 114 via suitable means, such as bonding. Next,each contact 104, in its uncrimped form (shown in FIG. 22), isincorporated into the housing 112. In particular, as shown in FIG. 11,the legs 128 of each contact 104 are inserted through the correspondingentry apertures 118 in the housing 102, through the corresponding entryapertures 136 in the seal 106, through the interior passage 112, throughthe corresponding exit apertures 138 in the seal 106, and out thecorresponding exit apertures 120 in the housing 102. As shown in FIG.23, the end portions 132 of the respective legs 128 of each contact 104extend from the housing 102. Next, the end portions 132 of the arms 128of each contact 104 are crimped away from each other until seated withinthe recess 124, as illustrated in FIGS. 9 and 11. Then, the electricalconductors (such as the electrical conductors 58 shown in FIG. 5) wouldbe attached (e.g., via welding) to the contacts 104. Next, the exteriorsurface of the housing 102 is overmolded with the electricallyinsulative cover (not shown).

Referring now to FIGS. 24-28, another embodiment of a connector 200 thatcan be incorporated into the extension lead 16 and/or neurostimulator 12(shown in FIGS. 1 and 2) will be described. Like the connector 100, theconnector 200 can receive the proximal end of an electrical lead, whichcan be firmly engaged and locked within the connector 200. Again, theelectrical lead may be, e.g., the stimulation lead 14 or the extensionlead 16 (shown in FIGS. 1 and 2). In contrast to the connector 100, theconnector 200 has a discrete end cap and allows for the seal to belaterally introduced into the housing, as well as allows for easierinjection molding of the housing (no blind core pins).

The connector 200 generally comprises (1) an electrically insulativehousing 202 for receiving the proximal end of the electrical lead; (2)the previously described plurality of electrical spring clip contacts104 (in this case, sixteen contacts) incorporated into the housing 202,such that contacts 104 firmly engage the terminals of an electrical leadthat is received into the housing 202; (3) an electrically insulativeseal 206 to ensure that the contacts 104, and thus the terminals inengagement with the contacts 104, are electrically isolated from eachother; (4) the previously described connector block 108 associated withthe housing 202 to lock the electrical lead within the housing 202; (5)an end cap 216 associated with the housing 202 to serve as an insertionstop for the electrical lead; and (6) an optional electricallyinsulative covering disposed over the housing 202.

Referring further to FIGS. 29 and 30, the housing 202 includes an outerwall 210, an interior passage 212 partially surrounded by the outer wall210, a port 214 into which the proximal end of the electrical lead canbe introduced, and an open end 217 opposite the port 214. In theillustrated embodiment, the outer wall 210 takes the form of an opencylinder that includes an axial slot 220 extending the length of theouter wall 210. The outer wall 210 may have the same composition anddimensions as those described above with respect to the outer wall 110.

Like the housing 102, the housing 202 accommodates the contacts 104using a pattern of apertures and recesses formed within the outer wall210 using suitable means, such as laser ablation or molding. The housing202 differs from the housing 102 in that it does not include contactexit apertures. Rather, the axial slot 116 serves as the exit point forthe contacts 104.

In particular, the housing 202 includes pairs of contact entry apertures218 extending through the outer wall 210. The housing 202 furtherincludes a channeled recess 222 formed in the exterior surface of theouter wall 210 adjacent each contact entry aperture pair 218. Thecontact entry apertures 218 and channel recesses 222 are respectivelyformed and arranged in the same manner as the contact entry apertures118 and channel recesses 122 described above. The housing 202 furtherincludes pairs of channeled recesses 224 formed in the exterior surfaceof the outer wall 210 adjacent the axial slot 220. In particular, thepairs of channeled recesses 224 are axially spaced along the outer wall210. The recesses 224 of each pair circumferentially extend from theaxial slot 220 in opposite directions and are axially aligned with arespective one of the channeled recesses 222.

As shown in FIGS. 25-28, the legs 128 of each contact 104 extend througha respective pair of contact entry apertures 218 into the interiorpassage 212 of the housing 202, such that the common portion 126 of therespective contact 104 is seated within the recess 222 extending betweenthe contact entry apertures 218, and the middle portions 130 of the legs128 firmly engage the respective electrical terminal (not shown)therebetween when the proximal end of the electrical lead is introducedinto the internal passage 112. Notably, the middle portions 130 of thecontact 104 are not shown bent outward (as in FIG. 11), but are shownstraight to illustrated an alternative means for engaging the electricalterminal of the electrical lead. The legs 128 of each contact 104further extend from the interior passage 212 of the housing 202 andthrough the axial slot 220, such that end portions 132 of the legs 128are disposed externally to the outer housing 202. The end portions 132of the legs 128 are curved outward back towards the common portion 126,such that they are seated within the respective recesses 224 extendingcircumferentially outwardly from the axial slot 220. As described above,the end portions 132 of the legs 128 may be curved using suitable means,such as a crimping tool. Preferably, the depth of the recesses 222, 224is equal to or greater than diameter of the wire from which the contact104 is formed, so that no portion of the common portions 126 or legs 128extends above the external surface of the outer wall 210.

Referring to FIGS. 27 and 28, the tubular seal 206 is disposed withinthe housing 202, and in particular, is interference fit with theinterior surface of the housing 202, such that seal 206 surrounds theinterior passage 212. The tubular seal 206 may be composed of anyelectrically insulative and compliant material, such as silicone.

Referring further to FIGS. 31 and 32, the tubular seal 206 includes acylindrical wall 234 having a diameter substantially the same as theinner diameter of the housing 202, such that the tubular seal 206 issnugly fit within the interior passage 212 of the housing 202. Thetubular seal 206 includes a first enlarged annular portion 235 disposedon end of the cylindrical wall 234 and a second enlarged annular portion237 disposed on the other end of the cylindrical wall 234. The length ofthe tubular seal 206 is such that the first enlarged annular portion 235extends externally from the port 214 (shown in FIG. 29), and the secondenlarged annular portion 237 extends externally from the open end 217(shown in FIG. 29). The tubular seal 206 includes pairs of contact entryapertures 236, pairs of contact exit apertures 238, and a plurality ofinner annular flanges 240 that are arranged and function in the samemanner as the contact entry apertures 136, contact exit apertures 138,and inner annular flanges 140 described above.

The annular flange 144 of the connector block 108 (shown in FIG. 20) ismounted within the first enlarged annular portion 235 of the tubularseal 206 using suitable means, such as bonding. The end cap 216 can becomposed of the same material as the outer housing 202 and is mountedwithin the second enlarged annular portion 237 of the tubular seal 206using suitable means, such as bonding. The electrical conductors (notshown) are respectively connected to the contacts 104 using suitabletechniques known in the art, such as welding. The electricallyinsulative cover is disposed over the housing 202 in such a manner thatall exposed surfaces of the contacts 104 are covered, and therebyelectrically insulated from each other if the connector 200 comes incontact with tissue or fluids.

Referring to FIGS. 33-35, a method of assembling the componentsillustrated in FIG. 24 into the connector 200 illustrated in FIGS. 25-27will now be described. First, as illustrated in FIG. 33, the seal 206 islaterally inserted into the interior passage 212 of the housing 202 viathe axial slot 220, such that the cylindrical wall 234 of the seal 206and housing 212 are interference fit with each other, and the enlargedannular portions 235, 237 of the tubular seal 206 reside outside of thehousing 212. As shown in FIG. 34, the annular flange 144 of theconnector block 108 is then inserted into the first enlarged annularflange 235 of the seal 206, and the end cap 216 is inserted into thesecond enlarged annular flange 237 of the seal 206. Next, each contact104, in its uncrimped form (shown in FIG. 22), is incorporated into thehousing 212. In particular, as shown in FIG. 28, the legs 128 of eachcontact 104 are inserted through the corresponding entry apertures 218in the housing 202, through the corresponding entry apertures 236 in theseal 206, through the interior passage 212, through the correspondingexit apertures 238 in the seal 106, and out the axial slot 220 in thehousing 202. As shown in FIG. 35, the end portions 132 of the respectivelegs 128 of each contact 104 extend from the housing 202. Next, the endportions 132 of the arms 128 of each contact 104 are crimped away fromeach other until seated within the recesses 224, as illustrated in FIGS.27 and 28. Then, the electrical conductors (such as the electricalconductors 58 shown in FIG. 5) would be attached (e.g., via welding) tothe contacts 104. Next, the exterior surface of the housing 202 isovermolded with the electrically insulative cover (not shown).

Referring now to FIGS. 36-42, still another embodiment of a connector300 that can be incorporated into the extension lead 16 and/orneurostimulator 12 (shown in FIGS. 1 and 2) will be described. Like theconnector 100, the connector 300 can receive the proximal end of anelectrical lead, which can be firmly engaged and locked within theconnector 300. Again, the electrical lead may be, e.g., the stimulationlead 14 or the extension lead 16 (shown in FIGS. 1 and 2). In contrastto the connector 100, the connector 300 has a discrete end cap, has ahousing that includes oblong or slotted contact entry and exitapertures, allows the spring clip contacts to be snapped into thehousing without crimping, and has individual seals.

The connector 300 generally comprises (1) an electrically insulativehousing 302 for receiving the proximal end of the electrical lead; (2) aplurality of electrical spring clip contacts 304 (in this case, sixteencontacts) incorporated into the housing 302, such that contacts 304firmly engage the terminals of an electrical lead that is received intothe housing 302; (3) a plurality of electrically insulative seals 306 toensure that the contacts 104, and thus the terminals in engagement withthe contacts 304, are electrically isolated from each other; (4) thepreviously described connector block 108 associated with the housing 302to lock the electrical lead within the housing 302; (5) an end cap 316associated with the housing 302 to serve as an insertion stop for theelectrical lead; and (6) an optional electrically insulative coveringdisposed over the housing 302.

Referring further to FIGS. 43-45, the housing 302 includes an outer wall310, an interior passage 312 partially surrounded by the outer wall 310,a port 314 into which the proximal end of the electrical lead can beintroduced, and an open end 317 opposite the port 314. The outer wall310 may have the same composition and dimensions as those describedabove with respect to the outer wall 110.

Like the housing 102, the housing 302 accommodates the contacts 304using a pattern of apertures formed within the outer wall 310 usingsuitable means, such as laser ablation or molding. The housing 302differs from the housing 102 in that it does not include separaterecesses for the contacts 204. Rather, a single recess is provided oneach side of the outer wall 310 for the contacts 104.

In particular, the housing 302 includes pairs of contact entry apertures318 and contact exit apertures 320 extending through the outer wall 310.The contact entry apertures 318 and contact exit apertures 320 arearranged in the same manner as the respective contact entry apertures118 and contact exit apertures 120 described above. The contact entryapertures 318 and contact exit apertures 320 respectively differ fromthe contact entry apertures 118 and contact exit apertures 120 in thatthey take the form of elongated holes or slots. The housing 302 furtherincludes a single recess 322 formed in the exterior surface of the outerwall 310 along the contact entry aperture pairs 318, and a single recess324 formed in the exterior surface of the outer wall 310 along thecontact exit aperture pairs 320.

As shown in FIG. 46, each of the contacts 304 is formed of a cylindricalwire that may be similar to the cylindrical wire from which each of thecontacts 104 is formed. Each of the contacts 304 includes a commonportion 326 and a pair of legs 328 extending downward from opposite endsof the common portion 326. The length of the common portion 326 equalsthe distance between the contact entry apertures 318 of each pair, suchthat the axes of the legs 328 will coincide with the contact entryapertures 318. The legs 328 respectively have middle portions 330configured for engaging the terminals of the electrical lead. Endportions 332 of the legs 328 are bent toward each other at a ninetydegree angle. The length of each of the respective legs 328 is greaterthan the distance between the corresponding apertures 318, 320 throughthe interior passage 312, such that the legs 328 can completely extendthrough the interior passage 312.

As shown in FIGS. 37-41, the legs 328 of each contact 304 extend througha respective pair of contact entry apertures 318 into the interiorpassage 312 of the housing 302, and the middle portions 330 of the legs328 firmly engage the respective electrical terminal (not shown)therebetween when the proximal end of the electrical lead is introducedinto the internal passage 312. The legs 328 of each contact 304 furtherextend from the interior passage 312 of the housing 302 and through therespective pair of contact exit apertures 320, such that end portions332 of the legs 328 are disposed externally to the outer housing 302.The end portions 332 of the legs 328 are curved inward, such that theyengage the recess 324.

Referring to FIG. 40-42, a plurality of seals 306 in the form of O-ringsare disposed within the housing 302, and in particular, are interferencefit with the interior surface of the housing 302, such that seals 306surround the interior passage 312. The tubular seal 306 may be composedof any electrically insulative and compliant material, such as silicone.As there shown, two seals 306 are disposed between each respective pairof contacts 304, such that when the proximal end of the electrical leadis inserted into the interior passage 312 and through center openings342 in the seals 306, the seals 340 will conform to, and thereby seal,against the outer surface of the electrical lead. As a result, even ifan electrolytic fluid enters the interior passage 312 of the outerhousing 302, the seals 306 will prevent or, at least minimize, theleakage of electrical current between the contacts 304.

The annular flange 144 of the connector block 108 (shown in FIG. 40) ismounted within the port 314 of the housing 320 using suitable means,such as bonding. The end cap 316 can be composed of the same material asthe outer housing 302 includes a boss 319 that is mounted within theopening 317 within the outer housing 302 using suitable means, such asbonding. The electrical conductors (not shown) are respectivelyconnected to the contacts 304 using suitable techniques known in theart, such as welding. The electrically insulative cover is disposed overthe housing 302 in such a manner that all exposed surfaces of thecontacts 304 are covered, and thereby electrically insulated from eachother if the connector 300 comes in contact with tissue or fluids.

A method of assembling the components illustrated in FIG. 36 into theconnector 300 illustrated in FIGS. 37-39 will now be described. First,the seals 306 and contacts 304 are alternatively incorporated intohousing 302. That is, two seals 306 are inserted into the interiorpassage 312 of the housing 302 via the port 314, such that the seals 306and housing 312 are interference fit with each other, and a contact 304is mounted to the housing 302. This is repeated until all of the seals306 and contacts 304 have been incorporated into the housing 302.

Each of the contacts 304 can be conveniently incorporated into thehousing 302 in a snap-fit arrangement. In particular, the legs 328 ofeach contact 304 are inserted through the corresponding entry apertures318 in the housing 302, through the interior passage 312, and throughthe corresponding exit apertures 320 in the housing 302. Notably, thecontact entry apertures 318 and contact exit apertures 320 are largeenough to allow the curved end portions 332 of the legs 328 to passthrough. Also, as shown in FIG. 48, as the end portions 332 of the legs328 pass through the contact exit apertures 320, the legs 328 are spreadapart by the force of the apertures 320 on the end portion 332. When theend portions 332 of the legs 328 completely pass through the respectivecontact exit apertures 320, the resilient or spring force of therespective contact 304 urges the legs 328 toward each other, therebyplacing the end portions 320 in engaging contact with the recess 324, asshown in FIG. 41.

Next, the annular flange 144 of the connector block 108 is inserted intothe port 314 of the housing 302, and the boss 319 of the end cap 316 isinserted into the opening 317 in the housing 302. Then, the electricalconductors (such as the electrical conductors 58 shown in FIG. 5) wouldbe attached (e.g., via welding) to the contacts 304. Next, the exteriorsurface of the housing 302 is overmolded with the electricallyinsulative cover (not shown).

Although particular embodiments of the present inventions have beenshown and described, it will be understood that it is not intended tolimit the present inventions to the preferred embodiments, and it willbe obvious to those skilled in the art that various changes andmodifications may be made without departing from the spirit and scope ofthe present inventions. Thus, the present inventions are intended tocover alternatives, modifications, and equivalents, which may beincluded within the spirit and scope of the present inventions asdefined by the claims.

1. An implantable connector for receiving an electrical lead bodyportion that carries an electrical terminal, comprising: an electricallyinsulative housing including an outer wall, an interior cavitysurrounded by the outer wall, a port through which the lead body portioncan be introduced into the interior cavity, and a pair of firstapertures disposed through the outer wall on a first side of thehousing; and an electrical spring clip contact mounted to the housing,the contact including a common portion and a pair of legs extending fromopposite ends of the common portion, the legs respectively extendingthrough the first apertures into the interior cavity, such that the legsfirmly engage the electrical terminal therebetween when the lead bodyportion is introduced into the interior cavity.
 2. The implantableconnector of claim 1, wherein the housing wall is cylindrical.
 3. Theimplantable connector of claim 1, wherein the housing is less compliantthen the legs.
 4. The implantable connector of claim 1, wherein thehousing further includes a recess within an external surface of thehousing between the first apertures, wherein the common portion isseated within the recess.
 5. The implantable connector of claim 4,wherein the recess has a depth, such that the common portion does notextend above the external surface of the housing.
 6. The implantableconnector of claim 1, wherein the housing further comprises at least oneopening disposed through the outer wall on a second side of the housingopposite the first side of the housing, wherein the legs extend from theinterior cavity through the at least one opening.
 7. The implantableconnector of claim 6, wherein the at least one opening comprises a pairof second apertures, and the legs respectively extend from the interiorcavity through the second apertures.
 8. The implantable connector ofclaim 6, wherein the at least one opening comprises an axial slotextending along a length of the outer wall, and the legs extend from theinterior cavity through the axial slot.
 9. The implantable connector ofclaim 6, wherein the housing further includes at least one recess withinan external surface of the housing adjacent the at least one opening,wherein ends of the legs are curved, such that they are seated withinthe at least one recess.
 10. The implantable connector of claim 1,wherein the portions of the legs within the interior cavity are radiusedoutward, such that the radiused portions at least partially wrap aroundthe electrical terminal when the lead body portion is introduced intothe interior cavity.
 11. The implantable connector of claim 1, furthercomprising a tubular seal disposed within the housing around theinterior cavity, the seal including a pair of apertures that are alignedwithin the first apertures, wherein the legs respectively extend throughthe apertures of the seal into the interior cavity of the receptacle.12. The implantable connector of claim 1, further comprising anelectrical conductor connected to the contact.
 13. The implantableconnector of claim 1, further comprising an electrically insulativecover disposed over the housing and common portion.
 14. The implantableconnector of claim 1, wherein the lead body portion carries a pluralityof electrical terminals, and wherein the housing further includes aplurality of pairs of first apertures disposed through the outer wall,the pairs of first apertures axially spaced apart along a length of thehousing, the implantable connector further comprising a plurality ofelectrical spring clip contacts mounted to the housing, each of thecontacts including a common portion and a pair of legs extending fromopposite ends of the common portion, the legs of each contactrespectively extending through a different pair of the first aperturesinto the interior cavity, such that the legs firmly engage a respectiveelectrical terminal therebetween when the lead body portion isintroduced into the interior cavity.
 15. An implantable lead assembly,comprising: the lead body portion of claim 1; and another electricallead having another lead body portion and the connector of claim 1carried by the other lead body portion.
 16. A method of manufacturingthe connector of claim 1, comprising inserting the legs through thefirst apertures into the interior cavity.
 17. The method of claim 16,further comprising inserting the legs from the interior cavity throughat least one opening disposed through the outer wall on a second side ofthe housing opposite to the first side of the housing.
 18. The method ofclaim 16, further comprising crimping each arm to form a radiusedportion, such that the radiused portions are disposed within theinterior cavity when the legs are respectively inserted through thefirst apertures.
 19. The method of claim 16, further comprisingintroducing a tubular seal into the interior cavity, wherein the legsare respectively introduced through a pair of apertures within the sealafter the legs are introduced through the pair of first apertures in theouter wall.
 20. The method of claim 16, further comprising applying anelectrically insulative cover to an exterior surface of the housing.